Magnetic toner applicator

ABSTRACT

A magnetic toner applicator for use in a magnetic printing system and which comprises a rotatable wheel of nonmagnetic material having a magnetized circumferential surface to which toner particles are adherent to form a circumferential layer of toner powder. The wheel is disposed for rotation in relation to a magnetic recording surface and serves as a source of toner for the recorded areas of the recording surface as the surface moves relative to the applicator wheel. The toner layer can also serve to minimize the spurious attraction of electrostatically charged toner particles to the recording surface.

United States Patent [191 Ott et a1.

[ MAGNETIC TONER APPLICATOR [75] Inventors: Owen J. Ott, Brookfield Center;

David W. Ginn, Newtown, both of Conn.

[73] Assignee: Data Interface, lnc., Danbury,

Conn.

[22] Filed: Apr. 5, 1974 21 Appl. No.: 458,176

[52] U.S. Cl. 118/637, 117/175 [51] Int. Cl G03g 13/06 [58] Field of Search 118/637; 117/175 [56] References Cited UNITED STATES PATENTS 3,392,432 7/1968 Naumann 117/17.5 3,553,464 1/1971 I 118/637 3,735,416 5/1973 Ott et al 178/6.6 A 3,739,749 6/1973 Kangas et al. 118/637 3,816,799 6/1974 Ott et a] 317/2 R [4 1 Jan. 14,1975

3,825,936 7/1974 Ott et al 118/637 Primary ExaminerMervin Stein Assistant Examiner-Douglas A. Salser Attorney, Agent, or Firm-Weingarten, Maxham & Schurgin [57] ABSTRACT A magnetic toner applicator for use in a magnetic printing system and which comprises a rotatable wheel of nonmagnetic material having a magnetized circum ferential surface to which toner particles are adherent to form a circumferential layer of toner powder. The wheel is disposed for rotation in relation to a magnetic recording surface and serves as a source of toner for the recorded areas of the recording surface as the surface moves relative to the applicator wheel. The toner layer can also serve to minimize the spurious attraction of electrostaticallycharged toner particles to the recording surface.

13 Claims, 7 Drawing Figures PATENTEDJARWHIS MAGNETIC TONER APPLICATOR FIELD OF THE INVENTION This invention relates to magnetic printers and more particularly to apparatus for applying toner particles to recorded areas of a recording surface.

BACKGROUND OF THE INVENTION In magnetic printing systems, magnetic imagesof information to be printed are recorded on a magnetic tape or other magnetizable surface, and magnetic toner is applied to the recorded areas for adherence thereto for subsequent transfer to a writing surface. A preferred system is shown for example in US. Pat. No. 3,735,416, entitled Magnetic Printing System, and assigned to the assignee of this invention. The toner is usually in fine powder form and is contained within supply apparatus which includes means for applying SUMMARY OF THE INVENTION In accordance with the invention, apparatus is provided for use in a magnetic printing system wherein a unitary means provides efficient application of toner to recorded areas of a recording surface while also being operative to remove spuriously attracted electrostatically charged particles from the recording surface. The invention comprises a rotatable cylindrical wheel of nonmagnetic material and which has a circumferential surface which is magnetized to attract toner particles which remain adherent thereto to provide a circumferential layer of toner'powder. The wheel is disposed for rotation in relation to the recording surface such that the layer of toner powder confronts and is in engagement with the recording surface toserve as a source of toner for the recorded areas thereof as the surface moves relative to the rotary wheel. This toner layer can also serve to minimize the spurious attraction of electrostatically charged toner particles .to the recording surface by providing a relatively higher conductivity path to discharge the spurious particles on the record-- ing surface, and to reduce spurious deposition of magnetic toner particles on the recording surface when electrostatically responsive optically innocuous diamagnetic particles are added to the magnetic toner.

DESCRIPTION OF THE DRAWING The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a cutaway pictorial view of a magnetic toner applicator according to the invention;

FIG. 2 is a sectional elevation view of the toner applicator of FIG. 1;

FIG. 3 is a cutaway pictorial view showing the applicator wheel and aperture plate of the embodiment of FIGS. 1 and 2;

FIG. 4 is a pictorial view of an alternative aperture plate useful in the invention; and

FIGS. 5-7 are cutaway pictorial views of alternatively magnetized toner applicators.

DETAILED DESCRIPTION OF THE INVENTION wall thereof through which toner is supplied to the housing. A hinged cover 18, including a resilient pad 20, can be provided to seal port 16 after toner is introduced into housing 10.

Attached to the top of housing 10 is a curved plate 22 which includes an aperture 24 across which tape 14 is caused to travel and through which toner is applied to the recording surface of tapel4. The tape follows a path and is in engagement with the confronting surface of plate 22 and passes around a guideblock 26 from which the tapecontinues in its path to a subsequent position for transfer of applied toner to a writing surface. A cylindrical wheel 28 is secured to and rotatable with a hollow shaft 30, such as by a hub portion 32 and set screw 34. Wheel 28 is of a nonmagnetic material, such as Lexan, and has around the periphery thereof a ring 36 of magnetic material which provides a circumferential magnetic surface confronting aperture 24. The ring 36 is typically a magnetic plastic material, such as Plastiform or Koroseal. In the illustrated embodiment the ring is adhesively affixed to wheel 28 by means of a groove provided around the periphery of the wheel.

' The specific manner and configuration of magnetization of ring 36 can take a variety of forms. The ring can be magnetized as shown in FIG. 5 to provide north and south poles on respective opposite side surfacessuch that the toner forms a tire around the outer periphery which is substantially uniform in thickness and density. Alternatively, ring 36 can be magnetized as in FIG. 6 with the outer cylindrical surface of one pole and the inner cylindrical surface, the other. As a further alternative, shown in FIG. 7, the ring can be magnetized to provide a plurality of radially extending dipoles, with one pole at the periphery and the other pole at the inner suface and with the spacing between sequential hered to ring 36 is in contact with the recording surface or closely adjacent thereto, such that toner particles become attached to the recorded areas of tape 14 as the tape passes across aperture 24. The periphery of ring 36 is a sufficient distance from the recording surface to not demagnetize the recorded areas thereof while permitting proper toner application. Typically, a l/32 inch gap is provided between the periphery of ring 36 and the recording surface. The toner layer adhered to ring 36 is typically 3/32 inch thick and thus engages the recording surface of the tape.

The shaft 30 is supported for rotation by the machine structure 40 such as by suitable bearings, not shown, and includes along the length thereof a helical spring 42 in engagement with the inside surface of shaft 30 and which functions as a helical conveyor for transport of toner powder from a reservoir, in which is collected toner removed from the tape surface after printing, back to housing for replenishing the toner supply for subsequent toner application and printing. The conveyor spring 42 is preferably of triangular crosssection, as illustrated, in order to enhance the conveying effect as spring 42 and shaft 30 is rotated. The toner conveying apparatus-is itself shown in the aforesaid U.S. Pat. No. 3,735,416, assigned to the present assignee.

First and second cams 44 and 46 are affixed to and rotatable with shaft 30 within housing 10. A cam follower 48 is affixed to one end of a plate 50, the other end of which is attached such as by a fastener 52 to structure 40. Plate 50 is wider than the width of tape 14 and is disposed in downwardly inclined disposition from the mounting end toward cam 46. A cam follower 54 is in contact with cam 44 and is coupled by a link 56 to a plate 58 which is disposed adjacent the inclined floor 60 of housing 10 and which is affixed, such as by fastener 62, at the end opposite to linkage 56.

The plate 58 is free to vibrate under the urging of a vibratory force imparted by cam 44 and transmitted via follower 54 and link 56. Plate 50 is also free to vibrate in response to vibratory forces transmitted by cam 46 via follower 48. The vibratory forces are typically provided by cam surfaces having a series of grooves disposed across the width of the cams to impart vibratory motion to the associated cam followers. Upon rotation of shaft 30, the vibrated plate 50 serves to convey toner particles falling from the recording surface of tape 14 downwardly along the surface of plate 50 for ultimate deposit into the housing chamber containing the toner supply. Vibrating plate 58 causes conveyance of toner particles falling from plate 50 toward the rotating wheel 28 for collection by magnetic ring 36 and subsequent application to the recording surface.

The end of slot 24 confronting magnetic ring 36 can have an inclined edge 64, as seen in FIG. 3, and which is inclined with respect to the direction of rotation of wheel 28 to plow toner from bead 38 onto the recording surface. Such an inclined aperture edge is not es sential but has been found desirable to enhance the amount of toner powder being applied to the tape surface. An alternative embodiment of the aperture plate is shown in FIG. 4 wherein the inclined edge of aperture 24 is increased in surface by a downwardly disposed lip 66 to provide a blade of greater thickness than edge 64.

The toner layer adhered to ring 36 provides a relatively dense mass of toner powder which is of use in the prevention of spurious deposition of toner particles which are electrostatically attracted to the recording surface of the tape. When an electrically conductive toner is employed, the toner mass provides a relatively higher conductivity than the more dispersed toner applied to the recording surface. The relatively high con- 6 ductivity of the toner mass surface is effective to remove the electrostatic charge of those particles spuriously attracted to the tape surface and upon being discharged, the spurious particles are removed from the tape surface leaving the intended particles magnetically adhered to the recorded areas of the tape. The provision of a dense toner mass for providing a conductive discharge path for removal of spuriously attracted toner particles is the subject of the aforesaid copending patent application Ser. No. 256,993. The toner can also include electrostatically responsive optically innocuous diamagnetic particles to prevent spurious attraction of magnetic toner particles to the recording surface.

The toner layer is effective to remove the spuriously attracted particles on the tape surface which become part of the toner mass. The toner applied to the magnetic recording areas of tape 14 is not materially affected and as tape 14 moves along its path in the printing system such toner, adhering to the recorded por' tions of the tape, is moved into a subsequent position for transfer onto a writing surface. As a result of the elimination of the spuriously attracted particles from the recording surface, the printed image provided by transfer of toner from the recording surface to a writing surface is substantially clean and sharp since spurious particles which could impair print quality are eliminated from the tape surface prior to imprinting of the recorded images.

According to a further embodiment of the invention, the aperture plate is of a magnetically permeable low remanence material such as soft iron or an iron-nickel alloy. This permeable plate causes the toner particles of layer 38 to form a radial chain of particles having maximum density in the region'directly between the bottom surface of the plate and the confronting periphery of ring 36. The toner mass is therefore more concentrated in this confronting region to provided higher conductivity or a more dense mass for more rapid elimination of spurious electrostatically attracted toner particles on the tape surface. The permeable plate also provides magnetic shielding to protect the magnetic images recorded on the tape surface from possible demagnetizing forces occasioned by proximity of the applicator wheel 28.

Various modifications and alternative implementations will occur to those versed in the art without departing from the true scope of the present invention. Accordingly, it is not intended to limit the invention by what has been particularly shown and described except as indicated in the appended claims.

What is claimed is:

1. In a magnetic printing system which includes a magnetic recording surface, means for applying toner to recorded areas of said surface and means for transferring such toner from said recording surface to a writing surface, toner supply apparatus comprising:

a housing containing a supply of toner and an aperture across which said recording surface is caused to move;

a rotary wheel of nonmagnetic material having a magnetic circumferential peripheral surface retaining a layer of toner thereon;

said toner layer being disposed in confronting relation to said aperture to contact said recording surface for attraction of toner to recorded areas thereof.

2. The invention according to claim 1 wherein said toner layer retained on the magnetic circumferential peripheral surface of said rotary wheel is of sufficient mass to provide a relatively high electrical conductivity discharge path for removal of electrostatically attracted toner particles from said recording surface.

3. The invention according to claim 1 wherein said housing includes a plate containing said aperture, said aperture being disposed across the width of said recording surface with the end of said aperture confronting said toner layer having an edge inclined with respect to the direction of rotation of said rotary wheel to plow toner from said toner layer onto said recording surface.

4. The invention according to claim 3 wherein said aperture includes a lip extending from said inclined edge toward said toner layer.

5. The invention according to claim 1 wherein said housing includes a first plate disposed in downwardly inclined disposition beneath said recording surface at a position to be confronted by a section of said recording surface after application of toner to recorded areas thereof;

means for vibrating said first plate to cause conveyance of toner particles falling from said recording surface along the length of said plate and into said housing for return to said toner supply therein;

a second plate disposed adjacent the floor of said housing in inclined disposition; and

means for vibration of said second plate to cause conveyance of toner particles on said second plate along the length of said plate toward said rotary wheel.

6. The invention according to claim 1 wherein said rotary wheel includes a ring of magnetic material providing said magnetic circumferential peripheral surface.

7. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with north and south poles on respective opposite side surfaces thereof.

8. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with the outer cylindrical surface being one pole and the inner cylindrical surface the opposite pole.

9. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with a plurality of radially extending dipoles.

10. The invention according to claim 1 wherein said housing includes a plate containing said aperture and being of a magnetically permeable low remanence material to cause the toner particles of said layer of toner on said rotary wheel to have maximum density in the confronting region between said plate and the periphery of said magnetic circumferential surface.

11. The invention according to claim 6 wherein said magnetic ring is of a magnetic plastic material affixed to said rotary wheel.

12. The invention according to claim 1 wherein said magnetic circumferential peripheral surface is spaced from said recording surface by an amount permitting toner application while not materially demagnetizing the recorded areas of said recording surface.

13. In a magnetic printing system which includes a magnetic recording surface, means for applying toner to recorded areas of said surface and means for transferring such toner from said recording surface to a writing surface, toner supply apparatus comprising:

a housing containing a supply of toner and an aperture across which said recording surface is caused to move;

a rotary wheel of nonmagnetic material having a magnetic circumferential peripheral surface retaining a layer of toner thereon, said total layer being disposed in confronting relation to said aperture for attraction of toner to recorded areas of said recording surface;

an elongated cylindrical tube supporting said rotary wheel for common rotation with said tube and including:

helical conveyor means within said tube for conveying toner to said housing;

a first plate disposed in downwardly inclined disposition beneath said recording surface at a position to be confronted by a section of said recording surface after application of toner to recorded areas of said surface; I

a second plate disposed adjacent the floor of said housing in inclined disposition toward said rotary wheel;

first cam means supported by and rotatable with said tube for vibrating said first plate to cause conveyance of toner particles falling from said recording surface along the length of said first plate and into said housing; and

second cam means supported by and rotatable with said tube for causing vibration of said second plate to cause conveyance of toner particles falling from said recording surface along the length of said second plate toward said rotary wheel. a:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENTNO.: 3,859,959

DATED I January 14, 1975 INVENTOR(S) Owen J. Ott and David W. Ginn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;

Column 2, line 13, "tranferring" should read -transferring.

Column 4, line 34, "provided" should read -provide--.

Column 5, line 27, insert -causing-- after "for".

Signed and Sealed this A rtes r:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflarents and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION" PATENT NO. 3,859, 959

DATED 1 January 14, 1975 INVENTOR(S) 1 Owen J. Ott and David W. Ginn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 13, "tranferring" should read --transferring-.

Column 4, line 34, "provided" should read --provide--.

Column 5, line 27, insert --causing-- after "for" Signed and Scaled this sixth D y of January 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uj'larenrs and Trademarks 

1. In a magnetic printing system which includes a magnetic recording surface, means for applying toner to recorded areas of said surface and means for transferring such toner from said recording surface to a writing surface, toner supply apparatus comprising: a housing containing a supply of toner and an aperture across which said recording surface is caused to move; a rotary wheel of nonmagnetic material having a magnetic circumferential peripheral surface retaining a layer of toner thereon; said toner layer being disposed in confronting relation to said aperture to contact said recording surface for attraction of toner to recorded areas thereof.
 2. The invention according to claim 1 wherein said toner layer retained on the magnetic circumferential peripheral surface of said rotary wheel is of sufficient mass to provide a relatively high electrical conductivity discharge path for removal of electrostatically attracted toner particles from said recording surface.
 3. The invention according to claim 1 wherein said housing includes a plate containing said aperture, said aperture being disposed across the width of said recording surface with the end of said aperture confronting said toner layer having an edge inclined with respect to the direction of rotation of said rotary wheel to plow toner from said toner layer onto said recording surface.
 4. The invention according to claim 3 wherein said aperture includes a lip extending from said inclined edge toward said toner layer.
 5. The invention according to claim 1 wherein said housing includes a first plate disposed in downwardly inclined disposition beneath said recording surface at a position to be confronted by a section of said recording surface after application of toner to recorded areas thereof; means for vibrating said first plate to cause conveyance of toner particles falling from said recording surface along the length of said plate and into said housing for return to said toner supply therein; a second plate disposed adjacent the floor of said housing in inclined disposition; and means for vibration of said second plate to cause conveyance of toner particles oN said second plate along the length of said plate toward said rotary wheel.
 6. The invention according to claim 1 wherein said rotary wheel includes a ring of magnetic material providing said magnetic circumferential peripheral surface.
 7. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with north and south poles on respective opposite side surfaces thereof.
 8. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with the outer cylindrical surface being one pole and the inner cylindrical surface the opposite pole.
 9. The invention according to claim 6 wherein said magnetic circumferential peripheral surface of said rotary wheel is magnetized with a plurality of radially extending dipoles.
 10. The invention according to claim 1 wherein said housing includes a plate containing said aperture and being of a magnetically permeable low remanence material to cause the toner particles of said layer of toner on said rotary wheel to have maximum density in the confronting region between said plate and the periphery of said magnetic circumferential surface.
 11. The invention according to claim 6 wherein said magnetic ring is of a magnetic plastic material affixed to said rotary wheel.
 12. The invention according to claim 1 wherein said magnetic circumferential peripheral surface is spaced from said recording surface by an amount permitting toner application while not materially demagnetizing the recorded areas of said recording surface.
 13. In a magnetic printing system which includes a magnetic recording surface, means for applying toner to recorded areas of said surface and means for transferring such toner from said recording surface to a writing surface, toner supply apparatus comprising: a housing containing a supply of toner and an aperture across which said recording surface is caused to move; a rotary wheel of nonmagnetic material having a magnetic circumferential peripheral surface retaining a layer of toner thereon, said total layer being disposed in confronting relation to said aperture for attraction of toner to recorded areas of said recording surface; an elongated cylindrical tube supporting said rotary wheel for common rotation with said tube and including: helical conveyor means within said tube for conveying toner to said housing; a first plate disposed in downwardly inclined disposition beneath said recording surface at a position to be confronted by a section of said recording surface after application of toner to recorded areas of said surface; a second plate disposed adjacent the floor of said housing in inclined disposition toward said rotary wheel; first cam means supported by and rotatable with said tube for vibrating said first plate to cause conveyance of toner particles falling from said recording surface along the length of said first plate and into said housing; and second cam means supported by and rotatable with said tube for causing vibration of said second plate to cause conveyance of toner particles falling from said recording surface along the length of said second plate toward said rotary wheel. 